This research is concerned with exploring the molecular basis of antibody formation at the chromosome level. One objective of this work will be to locate the structural genes for antibody heavy chains on a particular chromosome by hybridization in situ of labeled mRNA to mammalian chromosomes. A second aspect of the work will focus on immunospecific methods for isolating individual chromosomes and non-histone chromosomal proteins. Such procedures would considerably aid further studies on the structure and function of these important cell constituents. BIBLIOGRAPHIC REFERENCES: Bridges, S.H., and Fleischman, J.B. The structure of an immunoglobulin light chain fragment in mouse myeloma cells. J. Mol. Biol. 97: 11, 1975. Strahilevitz, M., Fleischman, J. B., Fischer, G.W., Harris, R., and Narasimhachari, M. Immunoglobulin levels in psychiatric patients and controls. Amer. J. Psychiatry 133: 772, 1976.